- The amplitude of a damped harmonic oscillator reduces exponentially with time. If the amplitude becomes \( \frac{1}{n} \) of its initial value after \( N \) oscillations, the relation is:
\[
A = \frac{A_0}{n^N}
\]
- Given that after 20 oscillations, the amplitude is \( \frac{1}{n} A_0 \), we can calculate the amplitude after 40 oscillations:
\[
A = \frac{A_0}{n^2}
\]